st: RE: what's wrong with this statement?

///
For me there is not errors in your lines.
Maybe there is something in the data. Try:
bys faccode pat_mrn admit_datetime discharge_datetime: count
RA
-----Mensaje original-----
De: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] En nombre de Jeph Herrin
Enviado el: Martes, 23 de Septiembre de 2008 02:16 p.m.
Para: statalist@hsphsun2.harvard.edu
Asunto: st: what's wrong with this statement?
I've done this many times (in the past) to identify duplicate records;
I've typed and retyped this several times. What's going wrong?
. bys faccode pat_mrn admit_datetime discharge_datetime: gen dups=_N
. tab dups
variable dups not found
r(111);
Notice, the first line does NOT produce an error. However, it also does
not produce a new variable!
Thanks in advance for pointing out what must be an obvious error.
Jeph
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
********************************************************************************
ADVERTENCIA: La información contenida en esta transmisión, y en cualquier archivo adjunto, está sujeta a reserva legal conforme a la normativa aplicable al Banco Central de Chile, y no puede ser usada o difundida por personas distintas de su o sus destinatarios. Si usted ha recibido esta transmisión por error, por favor notifique inmediatamente al remitente respondiendo por este mismo medio y elimínela de su sistema.
El Banco Central de Chile no se hará responsable de la exactitud y veracidad de la información contenida en este mensaje, así como de su modificación, copia, divulgación o reenvío, total o parcial. Su uso no autorizado puede ser sancionado de conformidad con las leyes chilenas.
El Banco Central de Chile transmite sus decisiones a través de comunicados oficiales, los que pone a disposición del público en su página de Internet: www.bcentral.cl
DISCLAIMER: The information contained in this email or any attached file, is subject to legal privilege pursuant to the laws and regulations applicable to the Central Bank of Chile , and may not be used or disseminated by any person other than its intended recipients. If you have received this transmission in error, please notify the sender immediately by reply to this email address and delete it from your system.
The Central Bank of Chile shall not be liable for the accuracy or authenticity of the contents of this message, whether amended, copied, forwarded or disclosed in any form, in whole or in part. Please note that unauthorized use may be penalized in conformity with the Chilean law.
The Central Bank of Chile communicates its decisions by official releases, and
makes them available to the public in its WebPages: www.bcentral.cl
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/